Related Experiment Video
Updated: May 14, 2026
12:26
Identification of Cyclin-dependent Kinase 1 Specific Phosphorylation Sites by an In Vitro Kinase Assay
Published on: May 3, 2018
Bipartite determinants mediate an evolutionarily conserved interaction between Cdc48 and the 20S peptidase
Dominik Barthelme1, Robert T Sauer
1Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
Summary
Proteasomes are vital ATP-dependent proteases. New findings show Cdc48, a protein, directly interacts with proteasomes, suggesting a broader role in cellular protein quality control beyond current understanding.
Area of Science:
- Biochemistry
- Molecular Biology
- Cell Biology
Background:
- Proteasomes are essential ATP-dependent proteases found in eukaryotes, archaea, and some bacteria.
- The 20S proteasome core functions with AAA+ unfolding rings like Cdc48 or proteasome-activating nucleotidase (PAN) in archaea, stabilized by C-terminal tripeptides.
- Eukaryotic dogma states Rpt(1-6) unfolding ring of the 19S regulatory particle is the sole AAA+ partner for the 20S proteasome.
Purpose of the Study:
- To investigate the interaction mechanisms between archaeal Cdc48 and the 20S proteasome.
- To explore the potential role of eukaryotic Cdc48 orthologs as direct partners of the 20S proteasome.
- To challenge the current understanding of AAA+ proteasome interactions in eukaryotes.
Main Methods:
- Structural analysis of archaeal Cdc48-20S proteasome interactions, identifying near-axial binding determinants.
- Biochemical assays to demonstrate mammalian Cdc48's ability to activate mammalian 20S proteasomes.
- Functional assays using a mouse Cdc48 variant to assess its role in protein degradation with 20S proteasomes.
Main Results:
- Archaeal Cdc48 utilizes distinct near-axial interactions, in addition to C-terminal tripeptides, to bind the 20S proteasome.
- Mammalian Cdc48 directly activates mammalian 20S proteasomes.
- A mouse Cdc48 variant demonstrated protein degradation activity in conjunction with 20S proteasomes.
Conclusions:
- Eukaryotic Cdc48 orthologs likely function directly with 20S proteasomes, expanding the known repertoire of proteasome-activating factors.
- These findings suggest a conserved mechanism for AAA+ proteasome interactions across archaea and eukaryotes.
- The direct interaction of Cdc48 with 20S proteasomes highlights its crucial role in maintaining intracellular protein quality control.
Related Concept Videos
02:17Separation of Sister Chromatids
At the transition from prophase to metaphase, there is a reduction in cohesion along the chromosomal arms, resulting in the resolution of sister chromatids. However, residual cohesin connections remain to hold the sister chromatids together until the transition from metaphase to anaphase. The residual connection prevents any premature separation of sister chromatids, blocking the risks of aneuploidy within the daughter cells.
At the onset of anaphase, separase, a proteolytic enzyme, is...
At the onset of anaphase, separase, a proteolytic enzyme, is...
00:50Anaphase Promoting Complex
The stepwise destruction of specific proteins is necessary for the progression and completion of the cell cycle. Such proteins are ubiquitinated by ubiquitin ligases and then subsequently destroyed by the proteasome. The SCF (Skp1/Cullin/F-box) and the anaphase-promoting complex (APC) are two important ubiquitin ligases involved in cell cycle progression. While SCF is active throughout the cell cycle, APC gets activated during metaphase to anaphase transition. Cdc20 or Cdh1 binds to APC and...
01:57Protein Complexes with Interchangeable Parts
Groups of proteins may form a complex where each protein in this complex has a different role in the overall execution of the complex’s function. Often some of the proteins in the complex can be replaced by a closely related variant to give a complex that contains many of the same components yet is functionally distinct.
The SCF ubiquitin ligase is a protein complex of five individual proteins. This complex attaches ubiquitin to other target proteins to mark them for degradation. In order to...
The SCF ubiquitin ligase is a protein complex of five individual proteins. This complex attaches ubiquitin to other target proteins to mark them for degradation. In order to...
02:19The Spindle Assembly Checkpoint
The spindle assembly checkpoint is a molecular surveillance mechanism ensuring the fidelity of chromosome segregation during anaphase. The checkpoint monitors the completion of all the prerequisite steps before chromosome segregation to determine whether the segregation process should proceed or be delayed.
Many proteins function together to control the spindle assembly checkpoint. Mutations affecting these proteins may allow cells to proceed into anaphase prematurely, resulting in the...
Many proteins function together to control the spindle assembly checkpoint. Mutations affecting these proteins may allow cells to proceed into anaphase prematurely, resulting in the...
01:33Coat Assembly and GTPases
Vesicles incorporate different coat protein subunits in different cell locations, which changes the properties of the coat, such as the shape and geometry of the transport vesicles. Thus, vesicle coat proteins also play a significant role in cargo selection.
Coat assembly depends on the local availability of phosphatidylinositol phosphates or PIPs and GTP-binding proteins. Adaptor proteins, which link the coat proteins to the membrane, bind to these PIPs and play a crucial role in controlling...
Coat assembly depends on the local availability of phosphatidylinositol phosphates or PIPs and GTP-binding proteins. Adaptor proteins, which link the coat proteins to the membrane, bind to these PIPs and play a crucial role in controlling...
02:34Inhibition of Cdk Activity
The orderly progression of the cell cycle depends on the activation of Cdk protein by binding to its cyclin partner. However, the cell cycle must be restricted when undergoing abnormal changes. Most cancers correlate to the deregulated cell cycle, and since Cdks are a central component of the cell cycle, Cdk inhibitors are extensively studied to develop anticancer agents. For instance, cyclin D associates with several Cdks, such as Cdk 4/6, to form an active complex. The cyclin D-Cdk4/6 complex...